Low molecular polymers (Mn of 500-10,000) containing hydroxyl-functionality (also referred to as polyols) are widely used in coating applications and are cured at room temperature or elevated temperatures using a variety of crosslinking technologies. The most typical crosslinkers are polyisocyanates and aminoplast resins. Polyisocyanate crosslinkers offer the advantages of low temperature cure and provide coatings with superior properties, but suffer from high toxicity, high cost and the limitation of balancing pot life with dry time. Aminoplast resins are often used as crosslinkers because they offer a good balance of lower cost and good coating performance, but curing at higher temperature is often required and they suffer from the toxicity of residual formaldehyde.
Accordingly there is a need for a new crosslinking technology under ambient conditions (or low temperature bakes, e.g. 60° C.). Furthermore there is need for coating properties when coating compositions are crosslinked while maintaining lower levels of toxicity.